The World No. 101 held his ground against the big-serving American, saving all nine break points he faced. Brown held two match points in the second set tie-break but failed to serve out the win. The 29 year old needed two hours and 19 minutes to claim the 6-4, 6-7(7), 7-6(4) victory over his opponent ranked No. 9 in the Emirates ATP Rankings. This was their first FedEx ATP Head2Head meeting.

"I got a little tight but you can’t practise those things," reflected Brown. "That’s just repetition of being in these situations, in matches against these guys. I’m really happy that this time I won it.”

Awaiting Brown in the quarter-finals is American Sam Querrey, who knocked out former champion and No. 7 seed Lleyton Hewitt 6-3, 6-4 in earlier Wednesday action.

Querrey, a finalist in 2010 (l. to Chela), capitalised on four of his five break points to defeat the former World No. 1 for the second time in five FedEx ATP Head2Head meetings. Hewitt won the Houston title in 2009.

Sixth-seeded Argentine Juan Monaco, the 2012 champion, became the fifth active player to reach 200 match wins on clay after defeating Indian Somdev Devvarman 7-6(4), 6-2 in first-round action. Read more

Top seeds Bob Bryan and Mike Bryan recorded their 15th consecutive ATP World Tour victory on Wednesday evening. The American twins defeated Australians Matthew Ebden and Samuel Groth 6-2, 3-6, 12-10 to secure their berth in the Houston semi-finals. The four-time champions (2007, ‘09-'11) picked up trophies at their last three events in Delray Beach, Indian Wells and Miami.